XML Schema

“XML Schema: Structures specifies the XML Schema definition language, which offers facilities for describing the structure and constraining the contents of XML 1.0 documents, including those which exploit the XML Namespace facility. The schema language, which is itself represented in XML 1.0 and uses namespaces, substantially reconstructs and considerably extends the capabilities found in XML 1.0 document type definitions (DTDs).”(http://www.w3.org/TR/xmlschema-1/ XML Schema Part 1: Structures Second Edition])

“An XML Schema consists of components such as type definitions and element declarations. These can be used to assess the validity of well-formed element and attribute information items (as defined in [XML-Infoset]), and furthermore may specify augmentations to those items and their descendants.”(http://www.w3.org/TR/xmlschema-1/ XML Schema Part 1: Structures Second Edition])